In copending U.S. patent application Ser. No. 656,793, filed Feb. 10, 1976 now abandoned, but refiled as a continuation, U.S. patent application Ser. No. 805,473 on June 10, 1977, there is disclosed a shovel tooth having a tooth holder portion extending forwardly from the shovel blade on which a tooth cap can be detachably fitted, a transverse web, and a rear portion fixedly attachable to the shovel blade, the rear portion being constructed as a U-shaped hollow shell with the free edges of the legs of the shell portion being fixedly connected with the shovel blade, as by welding. The web extends across and covers the edge of the shovel blade and provides support for the cap-holding portion.
The shovel tooth described therein can be used as a standard shovel tooth for equipping the shovels of equipment such as traveling loaders and excavators or dredging machines. If, however, very powerful forces act on the shovel tooth and are directed against the inside of the shovel or scoop, it is occasionally possible that the connection between the shovel tooth and the blade or scoop can become damaged. In order to provide adequate strength to withstand such extreme stresses, it is known to use teeth having a rear holder part on both the inside and the outside thereof. However, a disadvantage of such structures is that they can be used essentially only with a shovel blade having about the same wall thickness as the space between the two rear portions which must fit over the blade. This means that for each shovel blade wall thickness a different tooth model must be provided.
It is also known to use a cast lip instead of a shovel blade, as shown in U.S. Pat. No. 2,145,663. In this case the lip has thickened portions corresponding approximately to the two rear holder parts and is inserted in the front portion of the tooth. However, in the case of cast blades it is also disadvantageous that a different model is required for each construction. In addition, the service life of cast lips is considerably inferior to that of rolled blades.